1. Field of the Invention
The present invention relates to an optical pickup and an optical disc drive using the same, and more particularly to a reduction in electro-magnetic radiation.
2. Description of the Related Art
In an optical pickup that writes data on and reads data from a disc using a laser light beam and an optical disc drive using the same, such a problem is prone to occur in that electro-magnetic radiation and electro-magnetic interference are caused to the outside of the device in writing and reading data. In the case where the electro-magnetic radiation of the optical disc drive exceeds the limiting value defined according to the standard, the drive is not allowed to be shipped, and problems are the fundamental analysis of causes and schemes to take measures against the causes.
It is considered that a factor of electro-magnetic radiation in writing and reading data is electro-magnetic radiation in association with an LD drive current carried through a transmission line from a laser diode driver (LDD) to a laser diode (LD) in the optical pickup. The optical pickup includes at least one heat dissipation cover or more that dissipate the heat of the LDD and the LD, and the heat dissipation cover is also used for the purpose of shielding electro-magnetic radiation so as not to leak electro-magnetic radiation to the outside of the optical pickup. For a technique related to shielding electro-magnetic radiation, Japanese Patent Application Laid-Open Publication No. 2011-86336 and Japanese Patent Application Laid-Open Publication No. 2009-15998 are disclosed, for example.